Chromecast as mDNS Service in order toCast Screen Configuration on WLC Contents

IntroductionPrerequisitesRequirementsComponents UsedConfigureConfiguration ScenariosInitial ConfigurationChromecast and wireless client on same WLAN/VLANNetwork DiagramConfigurationChromecast and wireless client on different WLAN/VLANNetwork DiagramConfigurationForeing/Anchor scenarioNetwork DiagramConfigurationUsing DIAL serviceVerifyTroubleshoot

Introduction

This document describes how to configure Chromecast devices to act as a Bonjour serviceprovider. The use and administration of Chromecast devices on the networks is simplified by thesupport of Bonjour services. The _googlecast._tcp.local. service string allows Chromecastdevices to act as any other Bonjour service provider. This service is used exclusively in order tocast the screen of a supported device to the screen where Chromecast is connected.

This document focuses on how to mirror from a computer that runs Google Chrome to aChromecast device. For more information, see Cast a tab. 

This document is focused in applications and end devices (like smartphones) that uses mDNS todiscover Chromecast Devices. There will be some application or devices that will only try to lookfor Chromecast devices using Discovery and Launch (DIAL) service.

If our application and/or end device supports mDNS we can follow the Scenarios 1 to 3 but if ourapplication only supports DIAL service then Chromecast device and the end device used todiscover it must be on the same Virtual Local Area Network (VLAN) and in addition to that,Multicast forwarding needs to be enabled on the WLC. See Scenario 4 at the end of thisdocument.

To verify if our device/application supports mDNS and/or DIAL we can make a packet capture andcheck the queries sent by our device/application.

If we see queries sent only to 239.255.255.250 port UDP 1900 then our device/application onlysupport DIAL service discovery, if we also see queries sent to 224.0.0.251 port UDP 5353 thenour device/application also supports mDNS.

Example of DIAL querie:

Example of mDNS querie:

Prerequisites

Requirements

Cisco recommends you have basic knowledge of Bonjour services over a Wireless LAN Controller(WLC). For more information, see Manage Bonjour Services for BYOD.

The Chromecast device must be able to make Domain Name System (DNS) queries to 8.8.8.8,

otherwise it does not work.

Wireless clients that mirror screen-to-Chromecast do not need to have Internet access.

Components Used

The information in this document is based on these software and hardware versions:

WLC 5508 version 8.0.110.0●

WLC 2504 version 8.0.110.0●

Chromecast version 27946●

Access Point (AP) 3700i in local mode●

Laptop that runs Google Chrome version 42.0.x●

The information in this document was created from the devices in a specific lab environment. All ofthe devices used in this document started with a cleared (default) configuration. If your network islive, make sure that you understand the potential impact of any command.

Configure

Configuration Scenarios

This section describes these four configuration scenarios:

Chromecast and wireless clients on the same Wireless LAN (WLAN) and same VLAN1.Chromecast on WLAN A and wireless clients on WLAN B, different VLANs2.Chromecast on anchor WLC and wireless clients on foreign WLC3.Chromecast and wireless clients on different VLANs (same Service Set Identifier (SSID))4.

Initial Configuration

For all of the scenarios except for scenario 4, add the service string used by Chromecast whenyou cast on a screen. This allows the WLC to recognize a Chromecast device.

From the CLI:

>config mdns service create chromecast _googlecast._tcp.local. origin wireless

lss disable query enable

>show mdns service summary

Number of Services.............................. 7

Mobility learning status ........................ Enabled

Service-Name  LSS  Origin  No SP  Service-string

-------------------------------- ---- ---------- ----- ---------------

chromecast  No All 1 _googlecast._tcp.local.

From the GUI:

Choose Controller > mDNS > General. In the Master Services Database section of themDNS window, choose these settings: For Select Service, choose Other.For Service name,enter chromecast.For Service String, enter _googlecast._tcp.local..Check QueryStatus.For Origin, choose Wireless.

1.

Click Add when you are done.

The new Chromecast service appears in the multicast Domain Name System (mDNS)window:

2.

Add this service to the mDNS profile that is used on the WLAN. In this case the defaultprofile is used. From the CLI:>config mdns profilechromecast service add default-mdns-profile

>show mdns profile detailed default-mdns-profile

Profile Name..................................... default-mdns-profile

Profile Id....................................... 1

No of Services................................... 7

3.

Services......................................... AirPrint

AirTunes

AppleTV

HP_Photosmart_Printer_1

HP_Photosmart_Printer_2

Printer

chromecast From the GUI, choose Controller > mDNS > Profiles. Verify the profile name inthe Profile Name field and for Service Name, choose chromecast from the drop-down list.Click Add when you aredone.

Enable mDNS snooping. Choose Controller > mDNS > General and check the mDNSGlobal Snooping checkbox.

4.

Chromecast and wireless client on same WLAN/VLAN

Network Diagram

This diagram shows Chromecast and wireless clients on the same WLAN and VLAN.

Configuration

Create subinterface vlan 10. This interface has a Dynamic Host configuration Protocol(DHCP) server located on the same VLAN. From the CLI:>config interface create vlan10 10>config interface address dynamic-interface vlan10 192.168.10.15

255.255.255.0 192.168.10.254

>config interface port vlan10 1

>config interface mdns-profile vlan10 default-mdns-profile

1.

>config interface dhcp dynamic-interface vlan10 proxy-mode disable From the GUI:ChooseController > Interfaces and click New.

Enter the Interface Name and VLAN ID in the relevant fields. Click Apply.

The new interface appears on the screen. Click the new interface. In this example,

vlan10. In the Edit window,configure these fields: Port NumberVLAN IdentifierIP AddressNetmaskGatewaymDNSProfile

Create the WLAN with these settings: Security WPA2-PSK (password = cisco-chrome)Radiopolicy only 802.11gBy default mDNS snooping is enabled with default-profileMap it to vlan10From the CLI:>config wlan create 1 blue>config wlan security wpa akm 802.1x disable 1

>config wlan security wpa akm psk enable 1

>config wlan security wpa akm psk set-key ascii cisco-chrome 1

2.

>config wlan interface 1 vlan10

>config wlan radio 1 802.11g-only

>config wlan ccx aironetIeSupport disable 1

>config wlan enable 1 From the GUI:Choose WLANs > Create New and click Go.

Click the General tab and enter the information in the relevant fields as this example shows:

Click the Security tab followed by the Layer 2 tab. Configure the window as this exampleshows:

Click the Advanced tab and ensure that Aironet IE is not enabled. Then check the checkboxto Enable mDNS Snooping and choose default-mdns-profile from the mDNS Profile drop-down list.

Click Apply.

Connect the Chromecast and wireless client to this WLAN.3.

The Wireless client locates the Chromecast device and cast screen.4.

Chromecast and wireless client on different WLAN/VLAN

Network Diagram

This diagram shows Chromecast on WLAN A and wireless clients on WLAN B and differentVLANs.

Configuration

Add WLAN B for VLAN 20. See Steps 1 and 2 from Scenario 1 for more reference. >configinterface create vlan20 20

>config interface address dynamic-interface vlan10 192.168.20.15

255.255.255.0 192.168.20.254

>config interface port vlan20 1

>config interface mdns-profile vlan20 default-mdns-profile

>config interface dhcp dynamic-interface vlan20 proxy-mode disable

>config wlan create 2 red

>config wlan security wpa akm 802.1x disable 2

>config wlan security wpa akm psk enable 2

>config wlan security wpa akm psk set-key ascii cisco-chrome 2

>config wlan interface 2 vlan20

>config wlan radio 2 802.11g-only

>config wlan ccx aironetIeSupport disable 2

>config wlan enable 2

1.

Connect Chromecast to SSID blue.2.

Connect the wireless client to SSID red.3.

The Wireless client can now cast a screen to the Chromecast device.4.

Note: Smartphones are not able to find Chromecast for management in this scenario. Thisscenario has only been tested for screen mirroring.

Note: This scenario only works when APs are in local mode. For APs in flexconnect - localswitching, mirror only works if devices use the same VLAN (both Chromecast and laptop).

Foreing/Anchor scenario

Network Diagram

This diagram shows Chromecast on the anchor WLC and wireless clients on the foreign WLC.

Configuration

Create WLANs on both WLCs with identical settings. See Step 2 Scenario 1.1.Create a mobility domain between both WLCs. From the CLI:(WLC-Anchor) >show mobilitysummary

Mobility Protocol Port........................... 16666

Default Mobility Domain.......................... mb-anchor

Multicast Mode .................................. Disabled

Mobility Domain ID for 802.11r................... 0x5313

Mobility Keepalive Interval...................... 10

Mobility Keepalive Count......................... 3

Mobility Group Members Configured................ 1

Mobility Control Message DSCP Value.............. 0

Controllers configured in the Mobility Group

MAC Address  IP Address  Group Name  Multicast IP  Status

bc:16:65:c2:aa:c0 10.88.244.87  mb-anchor  0.0.0.0  Up

(WLC-Foreign) >show mobility summary

Mobility Protocol Port........................... 16666

Default Mobility Domain.......................... mb-foreign

Multicast Mode .................................. Disabled

Mobility Domain ID for 802.11r................... 0x25f5

Mobility Keepalive Interval...................... 10

Mobility Keepalive Count......................... 3

Mobility Group Members Configured................ 1

Mobility Control Message DSCP Value.............. 0

Controllers configured in the Mobility Group

MAC Address  IP Address  Group Name  Multicast IP  Status

6c:20:56:b8:ba:40 10.10.30.10  mb-foreign  0.0.0.0  Up

(WLC-Anchor) >config mobility group member add 6c:20:56:b8:ba:40 10.10.30.10 mb-foreign

(WLC-Foreign) >config mobility group member add bc:16:65:c2:aa:c0 10.88.244.87 mb-anchor

(WLC-Anchor) >show mobility summary

2.

Mobility Protocol Port........................... 16666

Default Mobility Domain.......................... mb-anchor

Multicast Mode .................................. Disabled

Mobility Domain ID for 802.11r................... 0x5313

Mobility Keepalive Interval...................... 10

Mobility Keepalive Count......................... 3

Mobility Group Members Configured................ 2

Mobility Control Message DSCP Value.............. 0

Controllers configured in the Mobility Group

MAC Address  IP Address  Group Name  Multicast IP  Status

6c:20:56:b8:ba:40  10.10.30.10  mb-foreign  0.0.0.0  Up

bc:16:65:c2:aa:c0  10.88.244.87  mb-anchor  0.0.0.0  Up

(WLC-Foreign) >show mobility summary

Mobility Protocol Port........................... 16666

Default Mobility Domain.......................... mb-foreign

Multicast Mode .................................. Disabled

Mobility Domain ID for 802.11r................... 0x25f5

Mobility Keepalive Interval...................... 10

Mobility Keepalive Count......................... 3

Mobility Group Members Configured................ 2

Mobility Control Message DSCP Value.............. 0

Controllers configured in the Mobility Group

MAC Address  IP Address  Group Name  Multicast IP  Status

6c:20:56:b8:ba:40 10.10.30.10  mb-foreign  0.0.0.0  Up

bc:16:65:c2:aa:c0 10.88.244.87  mb-anchor  0.0.0.0  Up

Configure a WLAN that is anchored in order to anchor the WLC. From the CLI:(WLC-Anchor)>config wlan disable 1

(WLC-Anchor) >config wlan mobility anchor add 1 10.88.244.87

(WLC-Anchor) >config wlan enable 1

(WLC-Foreign) >config wlan disable 1

(WLC-Foreign) >config wlan mobility anchor add 1 10.88.244.87

(WLC-Foreign) >config wlan enable 1 For GUI instructions, see Configuring Mobility Groups(GUI).

3.

Connect Chromecast to SSID blue on the anchor WLC.4.

Connect a laptop to SSID blue on the foreign WLC.5.

The laptop locates the Chromecast device for cast screen.6.

Using DIAL service

In order to discover Chromecast devices from smartphones/applications that only supports DIALservice we need to be sure that both of them are on the same vlan and multicast forwarding isenabled on the WLC. There are certain circumstances where they can be in different vlans. Formore details check the next document Chromecast Deployment Guide, Release 7.6

Verify

Use this section to confirm that your configuration works properly.

The Output Interpreter Tool (registered customers only) supports certain show commands. Usethe Output Interpreter Tool in order to view an analysis of show command output.

Check that the Chromecast device and wireless clients are connected to the right WLAN.>show client wlan 1

Number of Clients in WLAN........................ 1

MAC Address AP Name Status Auth Protocol Port Wired Mobility Role Device Type

----------------- ----------------- ------------- ---- ---------------- -----

80:d2:1d:4a:69:86 APe4c7.228a.4bf3 Associated Yes 802.11n(2.4 GHz) 1 No Local Unknown

00:f4:b9:0b:14:19 APe4c7.228a.4bf3 Associated Yes 802.11n(2.4 GHz) 1 No Local Unknown

chromecast mac address

wireless client mac address

1.

Check that the Chromecast device is detected by the WLC. >show mdns domain-name-ipsummary

Number of Domain Name-IP Entries................. 2

DomainName MAC Address IP Address Vlan Id Type TTL Time left

(sec) (sec)

-------------------- ---------------- ---------------- ------- ------ ------ ------

2.

Chromecastkcg.local. 80:d2:1d:4a:69:86 192.168.10.66 10 Wireless 4725 4411

>show mdns service detailed chromecast

Service Name..................................... chromecast

Service String................................... _googlecast._tcp.local.

Service Id....................................... 8

Service query status............................. Enabled

Service LSS status............................... Disabled

Service learn origin............................. Wireless

Number of Profiles............................... 1

Profile.......................................... default-mdns-profile

Number of Service Providers ..................... 2

Number of priority MAC addresses ................ 0

ServiceProvider MAC Address AP Radio MAC Vlan Id Type TTL Time left

(sec) (sec)

-------------------- ---------------- ---------------- ------- ------

Chromecastkcg._googlecast._tcp.local. 80:D2:1D:4A:69:86 34:DB:FD:0B:9C:90

10 Wireless 4500 4410

Chromecast's name

Troubleshoot

This section provides information you can use to troubleshoot your configuration.

The Output Interpreter Tool (registered customers only) supports certain show commands. Usethe Output Interpreter Tool in order to view an analysis of show command output.

Note: Refer to Important Information on Debug Commands before you use debugcommands.

Enter the debug mdns all enable command in order to troubleshoot this configuration.